How e-invoicing became non-negotiable for Payhawk's AP solution

AP isn't complete without e-invoicing

Payhawk is Bulgaria's first tech unicorn, and its ambition doesn't stop there. Its goal is to be the dominant spend management platform globally. But getting there comes with a built-in consequence: how to ensure its customers can receive locally compliant e-invoices.

Payhawk knew that a meaningful AP solution has to cover compliant invoicing in every market it wanted to operate in. "One of our core value propositions is to give customers one platform across regions, across different company processes," says Pavel Hadzhiev, Principal Product Manager at Payhawk. But invoicing, he adds, is "such a segmented problem to tackle, with different jurisdictions across almost every country in Europe."

Invoicing rules aren't a single spec to build, ship, and forget. Solving one country's mandate doesn't solve the next one either. Each country sets its own format, its own tax authority, its own network, and updates them on its own schedule. That turns e-invoicing into a feature that needs constant maintenance and support, with different requirements in every market.

For Payhawk, compliance shouldn't be the reason holding back its fast-paced growth. So it needed a solution that could keep pace with its own ambition.

"For the countries where there was mandatory e-invoicing, we generally just couldn't sell AP." — Pavel Hadzhiev, Principal Product Manager, Payhawk

Compliant e-invoicing as a core feature

Payhawk considered building its e-invoicing capability in-house, but knew that meant building a whole new company alongside their own, one with entirely different objectives competing for the same engineering time. "Even if we could do it on time for Belgium and Peppol, we wouldn't be able to maintain the pace of the evolving landscape," says Pavel.

Invopop became the engine behind compliant e-invoicing, embedded directly into Payhawk's platform. It's included in the AP plan by default, not sold separately. "We're not really selling invoicing as an additional module. We provide it completely free of charge as part of our accounts payable solution. We don't consider an AP platform which doesn't accommodate the invoicing regulations a meaningful solution for a customer," says Pavel. "Partnering with a solution like Invopop, which gives you one unified entry point into every European market, was very key," he adds.

In practice, that means a customer can now register to the relevant network, Peppol in Belgium, the PPF in France, directly from the Payhawk portal, and invoices route to Payhawk automatically as they're received. "The API is clean and capable. I was able to integrate it without much back-and-forth," says Alexander Delev, the Payhawk engineer who built the integration, highlighting that the documentation and support from the Invopop team made the first and following integrations easy to implement.

Belgium, the first market, took about 6 weeks to build. Every market since has taken about 2 weeks, as each new country runs through the same API pattern, leaving mostly country-specific detail to add on top of infrastructure that already exists. Payhawk is now live with Invopop in Belgium, France, Poland, Finland, and Italy, with more countries on the roadmap.

"In the beginning, it took us over a month to build the infrastructure. After that, just 2 weeks. Each new country is pretty easy to add on, because with the API we can reuse large parts of the work and just add country-specific details." — Alexander Delev, Senior Software Engineer, Payhawk

Building the modern financial stack for global businesses

Payhawk's ambition is to build a single platform for a finance team's spend, so teams don't need a different system per country. "The key problem to solve here is for multinational companies which operate in 10 or 15 countries. They don't need to be forced to use 5 different systems for AP because there's different invoicing mandates," says Pavel.

Global businesses are looking for a modern, flexible financial stack; choosing specialized tools for each need, cards, AP, AR, billing, ERP, that work together seamlessly, without needing a different vendor for the same function in every country they operate in.

That stack also needs to be AI-ready. Every invoice Payhawk now receives through Invopop arrives as structured data, which means it can be read, validated, and acted on, by Payhawk's own systems and by the AI-driven tools finance teams increasingly expect. A financial stack that can't act on its own data isn't built to withstand the future.

Invopop enables Payhawk to cover the AP side of that story today, and points toward a bigger one: a complete, AI-ready financial stack a company could run end to end, connected to its ERP, each piece handled by the right specialist, rather than any single vendor trying to poorly own it all.

What started as an embedded integration has become a deeper partnership, anchored in a shared view. Financial teams should be able to operate across countries without a patchwork of AP systems, and make their financial data useful, while staying compliant wherever a company operates.

"We've already started to establish Payhawk as the invoicing leader thanks to Invopop in Europe." — Pavel Hadzhiev, Principal Product Manager, Payhawk